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mrmikkelsen

1979 honda xl185s trials bike

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Yeah, what could go wrong?  What I really want is a 1979 Seeley Honda 'cause they stir my soul better than any other trials bike out there.  

Seeking to do an AHRMA trials in a couple of years, I notice that the modern classic rule book allows the 79 xl185s to be used for ahrma trials.  So I found a core bike and am researching what needs done to make a respectable trials bike that stays within the rules.   I don't see much evidence of others taking on this nonsensical project, but if anybody knows about it being done well, I'd love a steer toward learning more.  Here are the results of my early research:

Don't know rake angle, but targeting 27.5 degrees after I get my travel figured out.  Plan to cut and weld top tube ala Gary Jones cr250m approach.

Rear setting the foot pegs looks easy enough to get close.  I see lots of variance in positioning on various bikes.  Wonder what the driver is toward proper placement. I think modeling the TLR positioning is probably safe.

35mm forks from nx125 or 79 xl500s look like good starts to get trials fender mounting built in.   Bigger top out spring to bring travel down to 7".  No need to cut/weld damper rod to shorten I guess.

I'd love a Seeley sub fuel tank and tank cover.  I saw where I can buy a tank cover, but not the under tank.  I think sticking with the stock xl185 tank may be the starting point though it will look funky.  Looking for other options, like maybe a nice narrow cr125m tank.

Universal trials fenders are somewhat elusive so far.  Wondering if a ty175 rear fender will work well.  

Seats are pretty flat and small, making one from scratch to fit well should be okay.

Wonder what rear travel it should have.  No specs for any trials bike travel so far.  Need to look harder maybe?

200cc cylinder from an atc will bring larger finning and more displacement.  Atc200e camshaft a good choice?  Is  a Megacycle roller bearning torque cam a ton better?  Should the headpipe stay the same small stock xl185s size?  Will a bigger head pipe cause low end to suffer?  Carb size?  The Chinese ebay Mikuni carbs have a pretty small throat even on their "30mm" carbs.  Are they a good choice?  Gears from an xr have closer 1-2 gear ratios so I have a donor motor for that.  

Anyway, every single one of those thoughts is subject to change and I am very interested in getting more knowledgeable input on working through this project.  Thanks for any input you can offer!

 

 

 

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 Just buy a TL 125. ARMA sets easy sections anyways. Our Yamaha TY80 team could win any class they set.

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Back in the early 1980's, after being inspired by the works Honda of Eddie Lejune I decided to build just about what you are talking about. I was working at a Honda dealership which helped me resource parts.

i wanted to build 180lb or less single shocked Honda with the fuel tank under the seat for lowering the CG and centralizing weight.

i purchased a used XL, bought an oxy-acetylene torch and spent the winter in the cold garage building this. As it's been over 30 years I don't remember specifics of of measurements but I can list some of the features. The pictures may fill in some details. The wheels and forks and triple clamps were from a CR 125 in sure I modified the fork internals but don't remember what was done. I did cut the steering head and changed the fork rake and re located the handlebar clamps. The motor had a Poweroll big bore kit and stroked crank to make it about 222cc displacement.

I used the stock Keihin carb.  I fabricated an air box and fuel tank which can be seen located under the seat. The fuel was pumped up to the carb via a Mikuni vacuum pump. Swingarm was re enforced and a single Fox shock was made to specifications by Fox. The bodywork was made from a plastic trash can (yes this is true) which was formed with a heat gun and graphics were contact paper and stickers. The exhaust was stock header and the rest was fabbed and a WES muffler was fitted. Fenders were ft. Bultaco replica and rear a Preston Petty "Mudder". The fork brace was the inside of a streetbike fender held on with "U" bolts holding it on to the forks. 

I was young and inspired at the time and had a great time building it but you may be further down the road starting with a TL or something. It actually did work pretty well and while at the time I was riding intermediate and advanced class sections with it I'm sure it would have done quite well with the vintage sections today.

cheers and good luck!

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There is a Honda Xl185 trials special on the FB page "trials bikes for sale USA.  Was used in the AHRMA Modern Classic events.

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Hi,

If you go ahead with this project;

Take lots of progress pictures and post them in the projects section, we need more people doing this kind of thing.

As for the setup of the bike, Google "Trials Australia"

Go to "forums",

Then,"twinshock and classic  trials"

Then, "Steer clear, Understanding steering for twinshocks"

It will help you understand the issues and their effects on handling.

I built a highly modified bike with very steep steering angle,and the result is very good. But I think I got away with it because I got the C of G much lower and back a bit. Result drop-offs are no worse than my '97 gas gas, And there is no appreciable tuck in unless applying the front break with a lot of lock on, (again no different from a modern bike). I think a lot of this comes from the rear setup.

you will learn a lot from this project 

Good luck and enjoy. 

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Great input folks!  I hadn't checked in for some time and was happy to see the action.

I have almost bought several TL125's, but I always decide not to because they just aren't stirring it for me.  The reading on the steering angles has been helpful.  Cutting the steering head and rewelding at 27 degrees sounds about right to me.  Seeing how the pegs can be rear set is promisingsing too, got my eye on some of those universal weld on pegs on ebay.  I got some 35mm forks with fender mounts from an old dual sport model, and aluminum triples from an xr.  Ok really, I have about three donor bikes squirreled away under the deck.  I'd better stop doing that.  The bultaco style from fender and mudder sound good too.  I hope to find a tlr200 tank from 1979/80 that would be an easy fit and look more right than anything this side of custom bent trash cans- which by way is unimaginably cool.  Dang that conversion from your younger years is awesome.  Work won't begin for a while yet, there is a 41 dodge convertible that keeps commanding my attention and a smashed volvo that I think I can rebuild myself too.  Then a light resto on a ty175, then the bike I really want to build - this xl.  I'll post progress when I actually do something...

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this is based on a italian XL125s, which is quite identical with the XL185s sold worldwide, except the engine of course. head angle is standard, fork clamps are from a trials bike as are the forks (35 mm) and shocks. foot pegs are moved further back, height is different as well. tank seat unit is similar to the Honda RS 200 TS made by a friend. lot of work on the engine (250 cc, bored and stroked, gearbox has 6 speed with a very useable range - I changed the two sprockets for the 2nd gear, other are standard as on the 6speed italian XL125, primary drive is shorter, exhaust is hand made, pipe cames from a seeley, carb is a standard Keihin 22mm but I'm testing with a Keihin 24mm 

hope this can help

cheers 

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Edited by zisko62
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On 6/19/2017 at 2:23 AM, zisko62 said:

this is based on a italian XL125s, which is quite identical with the XL185s sold worldwide, except the engine of course. head angle is standard, fork clamps are from a trials bike as are the forks (35 mm) and shocks. foot pegs are moved further back, height is different as well. tank seat unit is similar to the Honda RS 200 TS made by a friend. lot of work on the engine (250 cc, bored and stroked, gearbox has 6 speed with a very useable range - I changed the two sprockets for the 2nd gear, other are standard as on the 6speed italian XL125, primary drive is shorter, exhaust is hand made, pipe cames from a seeley, carb is a standard Keihin 22mm but I'm testing with a Keihin 24mm 

hope this can help

cheers 

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Zisko, your bike is very cool.  I can't even tell your tank apart from the Seeley.  Very well done!  The Dodge is up and running, the TY175 is almost together, so I am almost ready to start building this long dreamed of Honda trials.  I should have a mess of stuff spread all over the place by the new year.   Thanks everybody!

 

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Work has finally begun!  

I am messing with the wheels first.  I still haven't found a set of 1979 xr185 wheels that would bolt right on, so I am working on another path to getting affordable alloy wheels.  A pair from a 1983 xr200r presented themselves, so I snapped them up.  

These wheels have similar hub configuration so the drilling angles should be spot on.  The aluminum rimmed XR200R wheels had larger gauge spokes than the xl185s, so the nipple body diameter is 0.015" different.  When I set the smaller nipples into the aluminum rim, that tiny bit of extra spacing is less than comforting in such a critical part of the bike.

How important is the clearance between the spoke nipple body diameter and the hole in the rim?

Here are the details:

0.245" spoke nipple body diameter
0.275" rim spoke hole diameter
0.355" Spoke nipple head outer diameter

Are these going to be okay for vintage trials use?  

Any thoughts are welcome. No guarantees are expected.

Thank you in advance,
Jon

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Spoke pictures are too boring, so here are some of the highlights of my starting point:

Yes, that is a construction eye-bolt re-purposed as a chain tensioner.  Brings back memories of working on farmer rigs at the motorcycle shop decades ago.

The brake lever pivot made out of electrical wire and a zip tie is pretty out there.  Who am I to be critical though, it was still working.

The last picture highlights the entire seat cover made out of some extremely strong black tape.  The duct tape seat cover I had as a kid was nowhere near this nice.  Catch that three foot long spark plug lead?  That same fine black tape was covering a huge crack in the hi-tension coil housing.  

I wonder what broke that actually put this bike out of commission?  

 

Say, does anybody have a decent set of 1976-78 Honda CR125M Elsinore triple clamps?  I need some 35mm triples for the replacement forks, and those would be perfect.  

Enjoy!

Jon  

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I've been playing with the Honda a bit recently.  I figure I need to get the rear suspension figured out first, then I can set up the front end with that done.  I got a set of Fox snowmobile shocks off ebay that were 14", an inch and a half shorter than stock so I could move the mounts forward on the swingarm and maybe get some snail type chain adjusters instead of the goofy eye-bolt style. With the shocks out of the way of the axle now, there is plenty of room for some smaller snail cams, like the TY175 has.  That plastic chain guide needed some trimming to move the rear mount up out of the way of the shock.  That mount used to be right where the shock is now.  Those springs sure look stout, wonder if they'll be okay.

 

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Seeing that old Honda XL 185 trials bike  reminds me of a friend of mines Honda 250 Super dream trials bike.

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The more I look at this goofy project, the more I think I want to make it into a trials bike, but with as much xl185s originality as possible.  Toward that end, I am swapping the left/right welded on footpeg mounts so rather than sticking out frontwards, they will stick out rearward.  This won't be quite as far backwards as may be ideal, but it will use all the stock hardware and so look as original as it can.  

AHRMA changed their trials bike class rules, adding a more modern twin shock class that includes Seeley's, Honda Reflex, and other similar models.  The modern classic class though still includes the Honda XL185S.  So maybe this would still have a better chance at being modern classic legal the more stock it looks.  Who really cares about the class frankly, it isn't like I am a competitive trials rider or anything.  I think I just want it to look original 'cause that's what I want.  Don't suppose I really need a reason, huh?  

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This project is a great break from reality.  The rear frame rails needed cut to allow the trials rear fender to fit in there.  The new fender mounts were cut from the removed fender loop, and the 1979 pennies soldered in nicely to cover the holes.  Now what would be super cool is to have the dual exhaust from a crf250r mounted up to each of those bulky eyelets a few inches forward.  Probably not going to do that, but sure am thinking about it.  

Does anybody know a good replacement gearbox or just first gear for this thing?  The 185 cases are supposed to be a bit narrower internally than what the newer 6 speed bikes require.  The gap is just a little wider between first and second than I'd like to see.  I've been scoring atv specs and only the xl125s looks to be equipped with  a narrower 6 speed transmission that importantly has a little tighter 1/2 gap.  Not much though, and I don't really need 6 speeds since I doubt I'll ever get beyond third.  

Back to grading papers for school.

Thanks,

Jon

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Looking forward to seeing your project progress. This is my xl185 conversion , I've added a chain tensioner since this picture

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